In a wireless communication network such as a Long-Term Evolution (LTE) network, there are certain/fixed data rate assignments for uplink (UL) and downlink (DL) data transmission between a user equipment and a base station (eNodeB) serving the user equipment.
In LTE systems and for DL transmission, there are 29, from 0 up to 28, possible rate assignments, denoted as modulation coding schemes (MCS). Moreover, in LTE systems and for UL transmission, there are 23 MCSs, from 0 to 22. Currently, data rates are assigned based on user equipment (UE) feedback (e.g., a channel quality indication (CQI), a pre-coding matrix indication (PMI), a rank indication (RI), a sounding reference signal (SRS), and a hybrid automatic repeat request (HARQ) acknowledgement (ACK) and/or negative acknowledgement (NACK)). As part of this rate assignment, changing the UL data rate or DL data rate based on the HARQ ACK/NACK feedback, is called link adaptation. Currently implemented algorithms for link adaptation are independent of network loading conditions and/or the assigned MCS.